The present invention relates to an improved seal with anti-theft device for items having rod-like portions.
Said seal is particularly suitable for application to the temples of eyeglasses.
It is in fact well-known that eyeglasses are currently commonly provided, in points of sale, with adapted seals bearing a customization marking or more simply the trademark of the manufacturer.
In recent times, in particular, it is common to integrate in the seals an anti-theft device which is able to activate electronic alarm circuits which are usually located near the exits.
The seals usually comprise a box-like body from which a tab protrudes which is constituted by articulated consecutive elements and is shaped so that it can be folded up so as to define, together with the box-like body, a seat for containing the rod-like portion of the item to which the seal is to be applied.
An electronic signaling component of a per se known type is inserted in the box-like body.
Moreover, the seal has a slider which irreversibly engages a guide rigidly coupled to the box-like body.
The slider has a mushroom-shaped head which enters and slides in a complementarily shaped seat defined in the tab so as to lock the tab in the folded position.
In this manner, the rod-like portion is retained in the seat defined by the folding of the tab by means of the irreversible locking of the slider.
In particular, the slider slides at right angles to the rod-like portion on the surface, defined by the box-like body, on which said rod-like portion rests.
The temple is in fact retained by the head of the slider and by the edge of the tab and is therefore retained along a plane which is parallel to the contact surface.
Although this type of seal ensures many advantages, it however suffers drawbacks.
First of all, the fact must be noted that the structure of the body of the seal allows a reduced sliding range for the slider, to the point that the slider can reach the end of its stroke without conveniently locking the rod-like portion.
Accordingly, in this type of seal there is provided a limited range of rod-like portions which can be retained therein without mutual rotations occurring.
For example, many problems can occur in trying to apply the anti-theft seal to items whose rod-like portions have a particularly small cross-section.
In addition to this, the dimensions of the anti-theft seal applied for example to the temples of eyeglasses causes many difficulties linked to the operations performed in order to arrange the eyeglasses in the exhibitors located in the points of sale.
The seals in fact can be applied to a temple without ensuring the locking of the temple in the containment seat and despite preventing uncoupling by sliding they can however rotate easily with respect to said temple, moving into an inclined position and thus making it difficult to perform the operations for arranging the eyeglasses in the exhibitors.
Moreover, currently commercially available seals also cannot be applied to items which have considerably large rod-like portions, since the containment seat that they define has a rather small cross-section with respect to the overall dimensions of the seal.
Moreover, currently widely used seals can be reused only partially, since in order to disengage them from the portions to which they have been previously applied it is necessary to break the mushroom-shaped head of the slider and therefore it is necessary to have a replacement part for the slider before being able to reuse the seal by applying it to a new rod-like portion.
In order to solve the cited drawbacks, a seal with anti-theft device has been provided which comprises a hollow body suitable to contain an electronic signaling component and defining a contact surface for a rod-like portion.
Two parallel and mutually opposite guides protrude from the body, each guide having at least one saw-tooth engagement surface for the irreversible sliding, at right angles to the contact surface, of a slider which has complementary saw-tooth engagement surfaces.
The rod-like portion is retained between the contact surface and a parallel contact surface arrangement formed by the slider.
A first gasket is arranged and glued on the hollow body in the region between the two guides.
A second gasket is instead arranged and glued on the lower face of the slider, interposed between the complementary saw-tooth engagement surfaces.
Although this new seal has achieved the intended aim, it still suffers the drawback that when it is closed on the corresponding rod-like portion the two elastomeric gaskets produce considerable friction on it.
Under traction, the friction effect is so intense as to overcome the adhesion force of the adhesive and the gaskets easily break off.
Accordingly, it is simple for an ill-intentioned person to slide the seal off the product and steal it.